| 摘要 |
PURPOSE:To reduce the noise power, by providing a driving circuit which not only generates a driving signal of the same phase as an input signal of a main phase detector but also generates such driving signal that the output of an auxiliary phase detector is minimum. CONSTITUTION:The input signal applied to a terminal 11 is amplified by an amplifier 12 and is given to a main phase detector 13. The output of the amplifier 13 is converted to a square wave by a zero comparator 16 and is given to an auxiliary phase detector 17. The reference signal applied to a terminal 17 has the waveform shaped by a waveform shaping circuit 20 and is converted to a lamp wave by a phase lock loop 21. This lamp wave is compared with the error output of a differential amplifier 18 and is given to a phase detector driving circuit 23. The driving circuit 23 generates two outputs of the same frequency as the reference signal and of phase difference 90 deg., and the output of the same phase as the input signal is given to the main phase detector 13, and the other output is given to the auxiliary phase detector 17. |
